Corona itself is completely unclassified now.
https://airandspace.si.edu/udvar-hazy-center
https://airandspace.si.edu/multimedia-gallery/si-97-15881-10...
https://airandspace.si.edu/multimedia-gallery/web10844-2008h...
They get heavy and expensive quick and consumer zoom lenses dont go that far.
How in the world were they able to build optics for satellites sattlies that could see such details on the ground?
It seems like magic to me.
It is also frustrating because I would love to have a lens based on that technology.
Like the person who put a QR code in to a mosaic tiled floor.
And it's technically true. They were calibrated with marks in the Arizona desert. Just not those big crosses.
> While a few sites are listed inside Arizona—near Fort Huachuca and Luke Air Force Base—they are comprised of the tri-bar optical test pattern used by the US government since the early 1950s, not 60-foot-wide concrete crosses.
It could all be false flag stuff:
•They actually were used for this stuff, but don't want to admit it.
•They weren't acctually used for this stuff, but want to make people think they were.
•They were designed for one purpose, built and paid for by that purpose, but then ultimately piggybacked being used by other services with plausible deniability.
Calibration has to be done somehow...
People really need to pay more attention to timelines. It's a pretty frequent occurrence that someone posts some pet theory of theirs, with links to support it, but the support evaporates (or is greatly weakened) when you actually look at the dates of their sources (e.g. trying to claim a news source is not credible because they reported then-reasonable speculative estimates in a time of great uncertainty (and were clear about what they were) that were contradicted years later by a more careful scientific study).
That said, these kinds of things are, necessarily, obvious and accessible to anyone. Calibration targets built for various programs are sometimes used for other programs, sometimes even by rival nations, simply because they're known to be there and it's easier to use something in place than to build something new. The fact that nearly all of these programs operated under great secrecy and before retention of classified records was typical (there were not yet as extensive of records retention mandates applicable to classified programs) means that the details can now be somewhat obscure, just because all of the original documentation was destroyed or lost after the program closed.
An interesting variety of calibration targets are those intended for radar (SAR) use, since they take the form of 3D shapes rather than 2D images. Since SAR is a much more recent technical development in remote sensing there are far fewer public details, but various military and contractor installations have included, at times, oddly carefully sculpted gravel piles that are assumed to serve this purpose. An example is at the former Lockheed site in Potrero Canyon near Beaumont, CA.
Many of the images covering the US taken by CORONA and several subsequent programs, mostly for calibration or testing but sometimes by error, were declassified under Clinton-era rules and given to the USGS. You can now browse them as part of USGS's general aerial imagery collection. The resolution is insufficient for most modern uses (the USGS's collection of agricultural aerial survey photos is far more useful), but they're unrivaled in the sheer land area they cover in one large frame.
https://www.google.com/maps/@30.3689672,-89.5662234,128m/dat...
https://www.google.com/maps/@30.3855351,-89.6284331,349m/dat...
https://www.ryanmercer.com/ryansthoughts/2011/11/17/40452107...
While the article does not really state anything, just positing more questions about its actual use, it seems like it is anyone’s guess due to the nature of the primary sources that knew the program being retirees or that the government gave this article writer all they felt comfortable with.
This makes me wonder: How many of these types of programs existed through the Cold War?
